video gone dark and green

I have had good video on zoom for years.  In last two weeks, my video has gone darkish and has a green cast.  I've tried playing around on video settings with no luck.  Did something change on defaults?  Help me figure out how to get back to a good video image.  (btw, I don't use any filters or backgrnds, so that isn't part of the problem.)  thanks for the help.